David Segui (r., below) leaves a federal court house after meeting with the grand jury investigating former New York Yankees pitcher Roger Clemens for perjury.

WASHINGTON - David Segui became the latest former major leaguer to appear before the federal grand jury investigating Roger Clemens for perjury, testifying for approximately 90 minutes Thursday.

Segui, dressed in a white dress shirt and shorts and sporting a porkpie hat, declined to discuss his testimony as he left the grand jury room on the third floor of the federal courthouse in the shadow of the Capitol.

Segui told the Daily News earlier this month that he didn't know if Clemens had ever used performance-enhancing drugs during his major league career, but his testimony could still be very important to Assistant United StatesAttorney Daniel P. Butler, the prosecutor leading the investigation into whether Clemens lied when he told Congress in 2008 that he had never used performance-enhancing drugs.

David Segui (r., below) leaves a federal court house after meeting with the grand jury investigating former New York Yankees pitcher Roger Clemens for perjury.

(Miller/News)

Segui told the Daily News earlier this month that he expected to be questioned about the vials, needles and blood-stained gauze that Clemens' former trainer Brian McNamee gave to investigators in 2008, claiming it was evidence that Clemens used steroids. McNamee told investigators he had told Segui about the medical waste about 10 years ago, when he was an assistant strength and conditioning coach with the Yankees.

If Segui confirmed McNamee's account during his appearance before the grand jury, as he was expected to, he would undermine one possible defense for Clemens if the former Yankee pitcher is ultimately charged with perjury. Clemens' attorney Rusty Hardin has claimed that McNamee manufactured the evidence to bolster his claims about Clemens' drug use in the Mitchell Report, which was released in December of 2007.

David Segui (r., below) leaves a federal court house after meeting with the grand jury investigating former New York Yankees pitcher Roger Clemens for perjury.

Anthony Corso, a Wall Street executive whom McNamee also told about the waste when he worked as his personal trainer, testified before the grand jury in April.

Segui, whose 15-season Major League Baseball career included parts of two seasons with the Mets, is the latest former ballplayer dragged into the Clemens investigation. Self-proclaimed steroid guru Jose Canseco appeared before the grand jury on June 3 and told reporters afterward that he testified that he had no evidence that Clemens had used performance-enhancing drugs. Former Yankee pitcher Jason Grimsley met with Butler and other investigators in August of 2009, and former pitcher Pedro Borbon Jr. has also been interviewed by investigators involved in the case.

McNamee told former Sen. George Mitchell that he injected the seven-time Cy Young Award winner with steroids and HGH at least 16 times. Clemens vehemently denied the allegations during a February 2008 congressional hearing on the Mitchell Report on steroid use in baseball. Congressional leaders said it appeared that Clemens had lied during the hearing and asked the Justice Department to investigate if the Rocket committed perjury.